Bottle brush trees (Callistemon spp.) are semi-evergreen plants trained to grow into multitrunked trees reaching 10 to 30 feet tall. The leaves are dark green on top and paler on the bottom. Bottle brush trees produce colourful flowers along 2- to 4-inch-long flower stems. Bottle brush trees grow outside without protection in U.S. Department of Agriculture plant hardiness zones 8 to 10. The best time to transplant bottle brush trees is when they are dormant in the early spring.
Loosen the soil to the depth of 36 inches with a shovel in a 6-foot circle. Choose a planting site located in full sun and containing moist, good-draining soil. Spread a 2-inch layer of coarse sand on top of the soil. Mix this into the loose soil and rake the soil level.
Dig a hole 24 inches deep and 36 inches across in the centre of the new planting site. Remove any rocks and sticks found in the soil. Rough the sides up with the edge of the shovel to prevent soil compaction.
Dig a trench 24 inches deep 3 feet around the bottle brush tree. Work the shovel downward and under the root ball. Slide a tarp under the root ball and lift the bottle brush tree out of the hole by grasping the edges of the tarp. Do not lift the tree by the stems since this could cause breakage.
Place the bottle brush tree in the prepared hole and slide the tarp out from under the root ball. Fill the hole with soil and firm it around the root ball to hold the tree in place. Soak the planting area with water to settle the soil. Add more soil if the soil sinks. Use the rest of the soil to fill in the hole created by the removal of the bottle brush tree.
Spread a 2- to 3-inch layer of organic mulch like wood chips around the base of the bottle brush tree. This reduces the growth of weeds and tree suckers. Keep the mulch 3 inches away from the trunk. Spread an even layer of white rocks around the tree to create a showplace.
Bottle brush trees die back in the winter in cold areas with freezing temperatures. Freezing weather prevents this plant from obtaining tree size. Protect the roots with a heavy layer of organic mulch so the plant will sprout again the following spring.
Do not plant bottle brush trees in heavy clay soil or soggy ground. A wet location causes bottle brush trees to develop root rot.